Theralion and Valiona make up the second boss encounter in Bastion of Twilight. The two dragons seem to be brother and sister. It should be noted that this is the same Valiona that is encountered in Grim Batol, where she abandons Drahga Shadowburner, leaving him to die within the dungeon while she escapes. It should also be noted that Valiona is the consort of Deathwing's son, Nefarian.[citation needed]

[Engulfing Magic]ωϖ—The Engulfing Magic increases damage and healing done by 100% and causes you to inflict Shadow damage equal to the damage or healing you do to allies within 10 yards, but does not harm you.

Theralion will fly into the air when pulled, Valiona will melee players. Players should be in a tight circle around Valiona so as to run through her when she casts Devouring Flames. Players need to spread out for Twilight Blast, but quickly group up when Blackout is cast so it can be safely dispelled.

Creating a designated point to collapse on to for Blackout helps. Blackout should be dispelled as quickly as possible after raiders collapse onto each other. Roughly 10 seconds after Blackout is cast, Devouring Flames will begin. Valiona will always cast Blackout first and alternate between Devouring Flames/Blackout until Theralion becomes active.

After two Blackouts Theralion will cast Dazzling Destruction. After three waves he will land and Valiona will take off. You will receive two Blackouts in the first round, and three blackouts in subsequent rounds. The third can come during dazzling destruction.

Phase 2: Valiona airborne, Theralion grounded.

Players should form a melee camp underneath Theralion's tail and a ranged camp so that Twilight Meteorite does not kill anyone.The ranged camp will need a direction to strafe in to avoid Fabulous Flames. Players who receive Engulfing Magic debuff should move into the space between the range/melee groups so as to avoid spreading damage to the raid. Moving in between the groups allows healers to still reach them, unless forced to stay due to being the target of a Twilight Meteorite in which case they should stop all casting.

After two Engulfing Magics Valiona will take a deep breath and fill one third of the room with flames. This occurs in an identical fashion to Felmyst in Sunwell Plateau. The flames will appear on either the North, South or Central area of the room. It helps to have a designated person call out where the flames will be.

It is recommended to use BL/Heroism if available when one of the DPS receives the Engulfing Magic debuff. After Deep Breath Valiona will land, Theralion will take off and the fight will reset to phase 1. Enrage timer is 10 minutes.